1. Field of the Invention
The present invention relates to a manufacturing method for a wax pattern for making a golf club head. More particularly, the present invention relates to the manufacturing method for prefabricating a first wax pattern to be joined to a second wax pattern in molding operation to form the wax pattern of the golf club head.
2. Description of the Related Art
A conventional manufacturing method for a golf club head typically includes the following steps:                1. Preparing a mold assembly and filling the mold assembly with liquid wax such that a wax pattern of a golf club head body is formed, when hardened, that permits opening the mold assembly for drawing out the wax pattern;        2. Dipping the wax pattern in slurry to produce a ceramic shell, and melting the wax in the ceramic shell by heating and pouring out the melting wax from the ceramic shell such that a mold cavity for the golf club head body is correspondingly formed in the ceramic shell;        3. Filling a melting metal into the ceramic shell and breaking the ceramic shell for drawing out a casting of the golf club head body when hardened, and the casting of the golf club head body having a connecting portion;        4. Manufacturing a club head component such as a striking plate and weight member by one of dewaxing, casting, forging or mechanical processing; and        5. Assembling the connecting portion of the casting of the golf club head body and the club head component by one of welding, adhesion, snap fitting or screw attachment to constitute the golf club head.        
The above-mentioned manufacturing method for the golf club head requires assembling multiple club head components. However, the conventional manufacturing method using separate club head components and golf club head body has several drawbacks. For example, there is unavoidably a good possibility of cracks existing or occurring between the golf club head body and club head components after assembling. Particularly, after the golf club head is in long-term use for striking a golf ball, a golf club head component such as a striking plate may be fallen off from the golf club head body by continuously exerting stresses resulted from striking. Furthermore, it is difficult in manufacturing and assembling the golf club head since the connecting portions of the golf club head body have several sophisticated structure for increasing an assembled relationship that may lengthen manufacture time and burden with manufacture cost.
Referring to FIGS. 1 through 3, Taiwanese Patent Publication No. 514,574, entitled “manufacturing method for a golf club head,” discloses an approach to the above problems. The manufacturing method includes the following steps:                1. Separately prefabricating two wax patterns 11, 12 of the golf club head, as shown in FIG. 1, by filling liquid wax into first and second individual mold assemblies (not shown) in molding operation, and drawing out the wax patterns 11, 12 such as a club-head wax pattern and a striking-plate wax pattern from the opened first and second mold assemblies;        2. Adhering the two wax patterns 11, 12 of the golf club head to form a one-piece design of the wax pattern in adhering operation, as shown in FIG. 1;        3. Dipping the combined wax pattern consisting of the two wax patterns 11, 12 in slurry, as shown in FIG. 2, to form a ceramic shell 13 of the golf club head in slurry-dipping operation, and melting the wax patterns 11, 12 of the golf club head in the ceramic shell 13 and pouring out the melting wax from the ceramic shell 13 in dewaxing such that a wax-pattern configuration (including a rear cavity) and a filling aperture of the ceramic shell 13 are correspondingly formed; and        4. Filling a molten iron into the ceramic shell 13 and breaking the ceramic shell 13 for drawing out a casting of the golf club head body 14 when hardened, as shown in FIG. 3.        
The casting of the golf club head body 14 is a one-piece member and has a rear cavity 141. In this case, the rear cavity 141 of the golf club head body is advantageously designed to have an undercut structure so as to improve striking ability or designs; even so, the manufacturing method for such an undercut structure of the golf club head body 14 has several drawbacks. For example, in adhering operation, connecting portions of the club-head wax pattern 11 and the striking-plate wax pattern 12 are connected each other by filling with liquid wax. Turning now to FIGS. 1a, 2a and 3a, there is a clearance (designated as “a” in FIG. 1a) existing between the connecting portions of the club-head wax pattern 11 and the striking-plate wax pattern 12 if the liquid wax cannot fill up a clearance formed therebetween. When this occurs, slurry can intrude into the clearance “a” between the club-head wax pattern 11 and the striking-plate wax pattern 12 in slurry-dipping operation. This results in remaining burrs (designated as “b” in FIG. 2a) in the ceramic shell 13 after dewaxing. Unavoidably, the burrs “b” of the ceramic shell 13 can result in forming a gap (designated as “c” in FIG. 3a) in the casting of the golf club head body 14. Consequently, it may deteriorate the quality of the golf club head body 14.
Besides, a filler such as liquid wax, resin, silica gel or hot melt adhesive (designated as a′ in FIG. 1b) can be used to fill the clearance “a” between the club-head wax pattern 11 and the striking-plate wax pattern 12. Typically, the filler a′ has a high degree of viscosity, exceeding 100 cps at 100° C. for example. For this reason it is difficult for the filler a′ to fill the clearance “a” between the club-head wax pattern 11 and the striking-plate wax pattern 12 in filling operation. Once dispensed, it is natuarlly very easy to cool and harden the filler a′ on the club-head wax pattern 11 and the striking-plate wax pattern 12 in filling operation. Even though the filler a′ can fill the clearance “a” in the intended manner, such a filler a′ may disadvantageously cause an irregular surface around the clearance “a” when hardened. Hence, there is a need for an additional procedure such as surface finishing for eliminating the irregular surface of the casting (not shown) of the golf club head body 14. This practice naturally necessitates a large operational space for inserting a tool in operating surface finishing. However, it is difficult to operate surface finishing in the rear cavity 141 of the casting of the golf club head body 14 where a space is limited. Hence, there is a need for improving the conventional manufacturing method for the wax pattern of the golf club head.
The present invention intends to provide a wax pattern of a golf club head and a manufacturing method therefor, wherein prefabricating a first wax pattern to be joined to a second wax pattern in molding operation to form a hybrid one-piece design of the wax pattern of the golf club head. The one-piece wax pattern of the golf club head accomplishes a smooth surface between connecting portions of the first and second wax patterns in one-step in such a way to mitigate and overcome the above problem.